The present invention relates to a coiling process and apparatus involving the radial winding of a filament. It also relates to the composite members obtained by this process.
The term composite is used to define materials made from a thermosetting resin mould reinforced with filaments, for example carbon or glass filaments. It is known that composite members with continuous, correctly oriented fibres have the best mechanical characteristics.
French Pat. No. 2 359 695, filed on July 27, 1979 discloses bodies of revolution obtained by winding a continuous thermosetting polymer-impregnated filament on to a mandrel between two side plates, followed by the setting of the polymer. Following baking, a composite member with a circular structure is obtained.
Different shell shapes are also known in which the filament is wound at a non-negligible distance from the mandrel axis in accordance with geodesic lines or lines which are close thereto.
Other composite members are known which are produced by the use of unidirectional sheets, sometimes supplied in preimpregnated form, which are shaped in a press. However, unlike in the above cases the fibres are not taut during the hardening of the mould and are not therefore arranged in such a way that optimum mechanical characteristics are obtained. This disadvantage is exacerbated by the overlapping of the warp and weft filaments if the reinforcing sheet is a fabric.